Methods of using atomized particles for electromagnetically induced cutting

ABSTRACT

An electromagnetically induced cutting mechanism which can provide accurate cutting operations on both hard and soft materials is disclosed. The electromagnetically induced cutter is capable of providing extremely fine and smooth incisions, irrespective of the cutting surface. Additionally, a user programmable combination of atomized particles allows for user control of various cutting parameters. The various cutting parameters may also be controlled by changing spray nozzles and electromagnetic energy source parameters. Applications for the, cutting mechanism include medical, dental, industrial (etching, engraving, cutting and cleaning) and any other environments where an objective is to precisely remove surface materials without inducing thermal damage, uncontrolled cutting parameters, and/or rough surfaces inappropriate for ideal bonding. The cutting mechanism further does not require any films of water or any particularly porous surfaces to obtain very accurate and controllable cutting.

This application is a divisional of U.S. application ser. No.08/522,503, filed Aug. 31, 1995, which issued into U.S. Pat. No.5,741,247 on Apr. 21, 1998.

BACKGROUND OF THE INVENTION

The present invention relates generally to a device for cutting bothhard and soft materials and, more particularly, to a device forcombining electromagnetic and hydro energies for cutting and removingboth hard and soft tissues.

Turning to FIG. 1, a prior art optical cutter for dental use isdisclosed. According to this prior art apparatus, a fiber guide tube 5,a water line 7, an air line 9, and an air knife line 11 (which suppliespressurized air) are fed into the hand-held apparatus 13. A cap 15 fitsonto the hand-held apparatus 13 and is secured via threads 17. The fiberguide tube 5 abuts within a cylindrical metal piece 19. Anothercylindrical metal piece 21 is a part of the cap 15.

When the cap 15 is threaded onto the hand-held device 13, the twocylindrical metal tubes 19 and 21 are moved into very close proximity ofone another. A gap of air, however, remains between these twocylindrical metal tubes 19 and 21. Thus, the laser within the fiberguide tube 5 must jump this air gap before it can travel and exitthrough another fiber guide tube 23. Heat is dissipated as the laserjumps this air gap.

The pressurized air from the air knife line 11 surrounds and cools thelaser as the laser bridges the gap between the two metal cylindricalobjects 19 and 21. Thus, a first problem in this prior art apparatus isthat the interface between the two metal cylindrical objects 19 and 21has a dissipation of heat which must be cooled by pressurized air fromthe air knife line 11. (Air from the air knife line 11 flows out of thetwo exhausts 25 and 27 after cooling the interface between elements 19and 21.) This inefficient interface between elements 19 and 21 resultsfrom the removability of the cap 15, since a perfect interface betweenelements 19 and 21 is not achieved.

The laser energy exits from the fiber guide tube 23 and is applied to atarget surface within the patient's mouth, according to a predeterminedsurgical plan. Water from the water line 7 and pressurized air from theair line 9 are forced into the mixing chamber 29. The air and watermixture is very turbulent in the mixing chamber 29, and exits thischamber through a mesh screen with small holes 31. The air and watermixture travels along the outside of the fiber guide tube 23, and thenleaves the tube and contacts the area of surgery. This air and waterspray coming from the tip of the fiber guide tube 23 helps to cool thetarget surface being cut and to remove cut materials by the laser. Theneed for cooling the patient surgical area being cut is another problemwith the prior art.

In addition to prior art systems which utilize laser light from a fiberguide tube 23, for example, to cut tissue and use water to cool this cuttissue, other prior art systems have been proposed. U.S. Pat. No.5,199,870 to Steiner et al., which issued on Apr. 6, 1993, discloses anoptical cutting system which utilizes the expansion of water to destroyand remove tooth material. This prior art approach requires a film ofliquid having a thickness of between 10 and 200 mm. Another prior artsystem is disclosed in U.S. Pat. No. 5,267,856 to Wolbarsht et al.,which issued on Dec. 7, 1993. This cutting apparatus is similar to theSteiner et al. patent, since it relies on the absorption of laserradiation into water to thereby achieve cutting.

Similarly to the Steiner et al. patent, the Wolbarsht et al. patentrequires water to be deposited onto the tooth before laser light isirradiated thereon. Specifically, the Wolbarsht et al. patent requireswater to be inserted into pores of the material to be cut. Since manymaterials, such as tooth enamel, are not very porous, and since a highlevel of difficulty is associated with inserting water into the “pores”of many materials, this cutting method is somewhat less than optimal.Even the Steiner et al. patent has met with limited success, since theprecision and accuracy of the cut is highly dependent upon the precisionand accuracy of the water film on the material to be cut. In many cases,a controllable water film cannot be consistently maintained on thesurface to be cut. For example, when the targeted tissue to be cutresides on the upper pallet, a controllable water film cannot bemaintained.

The above-mentioned prior art systems have all sought in vain to obtain“cleanness” of cutting. In several dental applications, for example, aneed to excise small amounts of soft tissues and/or hard tissues with agreat degree of precision has existed. These soft tissues may includegingiva, frenum, and lesions and, additionally, the hard tissues mayinclude dentin, enamel, bone, and cartilage. The term “cleanness” ofcutting refers to extremely fine, smooth incisions which provide idealbonding surfaces for various biomaterials. Such biomaterials includecements, glass ionomers and other composites used in dentistry or othersciences to fill holes in structures such as teeth or bone where toothdecay or some other defect has been removed. Even when an extremely fineincision has been achieved, the incision is often covered with a roughsurface instead of the desired smooth surface required for idealbonding.

One specific dental application, for example, which requires smooth andaccurate cutting through both hard and soft tissues is implantology.According to the dental specialty of implantology, a dental implant canbe installed in a person's mouth when that person has lost his or herteeth. The conventional implant installation technique is to cut throughthe soft tissue above the bone where the tooth is missing, and then todrill a hole into the bone. The hole in the bone is then threaded with alow-speed motorized tap, and a titanium implant is then screwed into theperson's jaw. A synthetic tooth, for example, can be easily attached tothe portion of the implant residing above the gum surface. One problemassociated with the conventional technique occurs when the cliniciandrills into the patient's jaw to prepare the site for the implant. Thisdrilling procedure generates a great deal of heat, corresponding tofriction from the drilling instrument. If the bone is heated too much,it will die. Additionally, since the drilling instrument is not veryprecise, severe trauma to the jaw occurs after the drilling operation.The drilling operation creates large mechanical internal stress on thebone structure.

SUMMARY OF THE INVENTION

The present invention discloses an electromagnetically induced cuttingmechanism, which can provide accurate cutting operations on hard andsoft tissues, and other materials, as well. The electromagneticallyinduced cutter is capable of providing extremely fine and smoothincisions, irrespective of the cutting surface. Additionally, a userprogrammable combination of atomized particles allows for user controlof various cutting parameters. The various cutting parameters may alsobe controlled by changing spray nozzles and electromagnetic energysource parameters. Applications for the present invention includemedical, dental, industrial (etching, engraving, cutting and cleaning)and any other environments where an objective is to precisely removesurface materials without inducing thermal damage, uncontrolled cuttingparameters, and/or rough surfaces inappropriate for ideal bonding. Thepresent invention further does not require any films of water or anyparticularly porous surfaces to obtain very accurate and controllablecutting.

Drills, saws and osteotomes are standard mechanical instruments used ina variety of dental and medical applications. The limitations associatedwith these instruments include: temperature induced necrosis (bonedeath), aerosolized solid-particle release, limited access, lack ofprecision in cutting depth and large mechanical stress created on thetissue structure. The electromagnetically induced mechanical cutter ofthe present invention is uniquely suited for these dental and medicalapplications, such as, for example, implantology. In an implantologyprocedure the electromagnetically induced mechanical cutter is capableof accurately and efficiently cutting through both oral soft tissuesoverlaying the bone and also through portions of the jawbone itself. Theelectromagnetically induced mechanical cutter of the present inventiondoes not induce thermal damage and does not create high internalstructural stress on the patient's jaw, for example. After the patient'sjaw is prepared with the electromagnetically induced mechanical cutter,traditional methods can be employed for threading the hole in thepatient's jaw and inserting the dental implant. Similar techniques canbe used for preparing hard tissue structures for insertion of othertypes of medical implants, such as pins, screws, wires, etc.

The electromagnetically induced mechanical cutter of the presentinvention includes an electromagnetic energy source, which focuseselectromagnetic energy into a volume of air adjacent to a targetsurface. The target surface may be a tooth, for example. A user inputdevice specifies whether either a high resolution or a low resolutioncut is needed, and further specifies whether a deep penetration cut or ashallow penetration cut is needed. An atomizer generates a combinationof atomized fluid particles, according to information from the userinput device. The atomizer places the combination of atomized fluidparticles into the volume of air adjacent to the target surface. Theelectromagnetic energy, which is focused into the volume of air adjacentto the target surface, is selected to have a wavelength suitable for thefluid particles. In particular, the wavelength of the electromagneticenergy should be substantially absorbed by the atomized fluid particlesin the volume of air adjacent to the target surface to thereby explodethe atomized fluid particles. Explosion of the atomized fluid particlesimparts mechanical cutting forces onto the target surface.

The user input device may incorporate only a single dial for controllingthe cutting efficiency, or may include a number of dials for controllingthe fluid particle size, fluid particle velocity, spray cone angle,average laser power, laser repetition rate, fiberoptic diameter, etc.According to one feature of the present invention, the atomizergenerates relatively small fluid particles when the user input specifiesa high resolution cut, and generates relatively large fluid particleswhen the user input specifies a low resolution cut. The atomizergenerates a relatively low density distribution of fluid particles whenthe user input specifies a deep penetration cut, and generates arelatively high density distribution of fluid particles when the userinput specifies a shallow penetration cut. A relatively small fluidparticle may have a diameter less than the wavelength of theelectromagnetic energy and, similarly, a relatively large fluid particlemay have a diameter which is greater than the wavelength of theelectromagnetic energy.

The electromagnetic energy source preferably is an erbium, chromium,yttrium, scandium, gallium garnet (Er, Cr:YSGG) solid state laser, whichgenerates electromagnetic energy having a wavelength in a range of 2.70to 2.80 microns. According to other embodiments of the presentinvention, the electromagnetic energy source may be an erbium, yttrium,scandium, gallium garnet (Er:YSGG) solid state laser, which generateselectromagnetic energy having a wavelength in a range of 2.70 to 2.80microns; an erbium, yttrium, aluminum garnet (Er:YAG) solid state laser,which generates electromagnetic energy having a wavelength of 2.94microns; chromium, thulium, erbium, yttrium, aluminum garnet (CTE:YAG)solid state laser, which generates electromagnetic energy having awavelength of 2.69 microns; erbium, yttrium orthoaluminate (Er:YAL03)solid state laser, which generates electromagnetic energy having awavelength in a range of 2.71 to 2.86 microns; holmium, yttrium,aluminum garnet (Ho:YAG) solid state laser, which generateselectromagnetic energy having a wavelength of 2.10 microns; quadrupledneodymium, yttrium, aluminum garnet (quadrupled Nd:YAG) solid statelaser, which generates electromagnetic energy having a wavelength of 266nanometers; argon fluoride (ArF) excimer laser, which generateselectromagnetic energy having a wavelength of 193 nanometers; xenonchloride (XeCl) excimer laser, which generates electromagnetic energyhaving a wavelength of 308 nanometers; krypton fluoride (KrF) excimerlaser, which generates electromagnetic energy having a wavelength of248nanometers; and carbon dioxide (CO2), which generates electromagneticenergy having a wavelength in a range of 9.0 to 10.6 microns.

When the electromagnetic energy source is configured according to thepreferred embodiment, the repetition rate is greater than 1 Hz, thepulse duration range is between 1 picosecond and 1000 microseconds, andthe energy is greater than 1 millijoule per pulse. According to onepreferred operating mode of the present invention, the electromagneticenergy source has a wavelength of approximately 2.78 microns, arepetition rate of 20 Hz, a pulse duration of 140 microseconds, and anenergy between 1 and 300 millijoules per pulse. The atomized fluidparticles provide the mechanical cutting forces when they absorb theelectromagnetic energy within the interaction zone. These atomized fluidparticles, however, provide a second function of cleaning and coolingthe fiberoptic guide from which the electromagnetic energy is output.

The optical cutter of the present invention combats the problem of poorcoupling between the two laser fiberoptics of FIG. 1. The optical cutterof the present invention provides a focusing optic for efficientlydirecting the energy from the first fiberoptic guide to the secondfiberoptic guide, to thereby reduce dissipation of laser energy betweenthe first fiberoptic guide and the second fiberoptic guide. This opticalcutter includes a housing having a lower portion, an upper portion, andan interfacing portion. The first fiberoptic tube is surrounded at itsupper portion by a first abutting member, and the second fiberoptic tubeis surrounded at its proximal end by a second abutting member. A cap isplaced over the second fiberoptic tube and the second abutting member.Either fiberoptic tube may be formed of calcium fluoride (CaF), calciumoxide (CaO2), zirconium oxide (ZrO2), zirconium fluoride (ZrF),sapphire, hollow waveguide, liquid core, TeX glass, quartz silica,germanium sulfide, arsenic sulfide, and germanium oxide (GeO2).

The electromagnetically induced mechanical cutter of the presentinvention efficiently and accurately cuts both hard and soft tissue.This hard tissue may include tooth enamel, tooth dentin, tooth cementum,bone, and cartilage, and the soft tissues may include skin, mucosa,gingiva, muscle, heart, liver, kidney, brain, eye, and vessels.

The invention, together with additional features and advantages thereofmay best be understood by reference to the following description takenin connection with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conventional optical cutter apparatus;

FIG. 2 is an optical cutter with the focusing optic of the presentinvention;

FIG. 3 is a schematic block diagram illustrating the electromagneticallyinduced mechanical cutter of the present invention;

FIG. 4 illustrates one embodiment of the electromagnetically inducedmechanical cutter of the present invention;

FIG. 5 illustrates the present preferred embodiment of theelectromagnetically induced mechanical cutter of the present invention;

FIG. 6 illustrates a control panel for programming the combination ofatomized fluid particles according to the presently preferredembodiment;

FIG. 7 is a plot of particle size versus fluid pressure;

FIG. 8 is a plot of particle velocity versus fluid pressure;

FIG. 9 is a schematic diagram illustrating a fluid particle, a source ofelectromagnetic energy, and a target surface according to the presentinvention;

FIG. 10 is a schematic diagram illustrating the “grenade” effect of thepresent invention;

FIG. 11 is a schematic diagram illustrating the “explosive ejection”effect of the present invention;

FIG. 12 is a schematic diagram illustrating the “explosive propulsion”effect of the present invention;

FIG. 13 is a schematic diagram illustrating a combination of FIGS.10-12;

FIG. 14 is a schematic diagram illustrating the “cleanness” of cutobtained by the present invention; and

FIG. 15 is a schematic diagram illustrating the roughness of cutobtained by prior art systems.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 2 shows an optical cutter according to the present invention. Theoptical cutter 13 comprises many of the conventional elements shown inFIG. 1. A focusing optic 35 is placed between the two metal cylindricalobjects 19 and 21. The focusing optic 35 prevents undesired dissipationof laser energy from the fiber guide tube 5. Specifically, energy fromthe fiber guide tube 5 dissipates slightly before being focused by thefocusing optic 35. The focusing optic 35 focuses energy from the fiberguide tube 5 into the fiber guide tube 23. The efficient transfer oflaser energy from the fiber guide tube 5 to the fiber guide tube 23vitiates any need for the conventional air knife cooling system 11 (FIG.1), since little laser energy is dissipated. The first fiber guide tube5 comprises a trunk fiberoptic, which comprises one of calcium fluoride(CaF), calcium oxide (CaO2), zirconium oxide (ZrO2), zirconium fluoride(ZrF), sapphire, hollow waveguide, liquid core, TeX glass, quartzsilica, germanium sulfide, arsenic sulfide, and germanium oxide (GeO2).

FIG. 3 is a block diagram illustrating the electromagnetically inducedmechanical cutter of the present invention. An electromagnetic energysource 51 is coupled to both a controller 53 and a delivery system 55.The delivery system 55 imparts mechanical forces onto the target surface57. As presently embodied, the delivery system 55 comprises a fiberopticguide for routing the laser 51 into an interaction zone 59, locatedabove the target surface 57. The delivery system 55 further comprises anatomizer for delivering user-specified combinations of atomized fluidparticles into the interaction zone 59. The controller 53 controlsvarious operating parameters of the laser 51, and further controlsspecific characteristics of the user-specified combination of atomizedfluid particles output from the delivery system 55.

FIG. 4 shows a simple embodiment of the electromagnetically inducedmechanical cutter of the present invention, in which a fiberoptic guide61, an air tube 63, and a water tube 65 are placed within a hand-heldhousing 67. The water tube 65 is preferably operated under a relativelylow pressure, and the air tube 63 is preferably operated under arelatively high pressure. The laser energy from the fiberoptic guide 61focuses onto a combination of air and water, from the air tube 63 andthe water tube 65, at the interaction zone 59. Atomized fluid particlesin the air and water mixture absorb energy from the laser energy of thefiberoptic tube 61, and explode. The explosive forces from theseatomized fluid particles impart mechanical cutting forces onto thetarget 57.

Turning back to FIG. 1, the prior art optical cutter focuses laserenergy on a target surface at an area A, for example, and theelectromagnetically induced mechanical cutter of the present inventionfocuses laser energy into an interaction zone B, for example. The priorart optical cutter uses the laser energy directly to cut tissue, and theelectromagnetically induced mechanical cutter of the present inventionuses the laser energy to expand atomized fluid particles to thus impartmechanical cutting forces onto the target surface. The prior art opticcutter must use a large amount of laser energy to cut the area ofinterest, and also must use a large amount of water to both cool thisarea of interest and remove cut tissue.

In contrast, the electromagnetically induced mechanical cutter of thepresent invention uses a relatively small amount of water and, further,uses only a small amount of laser energy to expand atomized fluidparticles generated from the water. According to the electromagneticallyinduced mechanical cutter of the present invention, water is not neededto cool the area of surgery, since the exploded atomized fluid particlesare cooled by exothermic reactions before they contact the targetsurface. Thus, atomized fluid particles of the present invention areheated, expanded, and cooled before contacting the target surface. Theelectromagnetically induced mechanical cutter of the present inventionis thus capable of cutting without charring or discoloration.

FIG. 5 illustrates the presently preferred embodiment of theelectromagnetically induced mechanical cutter. The atomizer forgenerating atomized fluid particles comprises a nozzle 71, which may beinterchanged with other nozzles (not shown) for obtaining variousspatial distributions of the atomized fluid particles, according to thetype of cut desired. A second nozzle 72, shown in phantom lines, mayalso be used. The cutting power of the electromagnetically inducedmechanical cutter is further controlled by the user control 75. In asimple embodiment, the user control 75 controls the air and waterpressure entering into the nozzle 71. The nozzle 71 is thus capable ofgenerating many different user-specified combinations of atomized fluidparticles and aerosolized sprays.

Intense energy is emitted from the fiberoptic guide 23. This intenseenergy is preferably generated from a coherent source, such as a laser.In the presently preferred embodiment, the laser comprises an erbium,chromium, yttrium, scandium, gallium garnet (Er, Cr:YSGG) solid statelaser, which generates light having a wavelength in a range of 2.70 to2.80 microns. As presently preferred, this laser has a wavelength ofapproximately 2.78 microns. Although the fluid emitted from the nozzle71 preferably comprises water, other fluids may be used and appropriatewavelengths of the electromagnetic energy source may be selected toallow for high absorption by the fluid. Other possible laser systemsinclude an erbium, yttrium, scandium, gallium garnet (Er:YSGG) solidstate laser, which generates electromagnetic energy having a wavelengthin a range of 2.70 to 2.80 microns; an erbium, yttrium, aluminum garnet(Er:YAG) solid state laser, which generates electromagnetic energyhaving a wavelength of 2.94 microns; chromium, thulium, erbium, yttrium,aluminum garnet (CTE:YAG) solid state laser, which generateselectromagnetic energy having a wavelength of 2.69 microns; erbium,yttrium orthoaluminate (Er:YAL03) solid state laser, which generateselectromagnetic energy having a wavelength in a range of 2.71 to 2.86microns; holmium, yttrium, aluminum garnet (Ho:YAG) solid state laser,which generates electromagnetic energy having a wavelength of 2.10microns; quadrupled neodymium, yttrium, aluminum garnet (quadrupledNd:YAG) solid state laser, which generates electromagnetic energy havinga wavelength of 266 nanometers; argon fluoride (ArF) excimer laser,which generates electromagnetic energy having a wavelength of 193nanometers; xenon chloride (XeCl) excimer laser, which generateselectromagnetic energy having a wavelength of 308 nanometers; kryptonfluoride (KrF) excimer laser, which generates electromagnetic energyhaving a wavelength of 248 nanometers; and carbon dioxide (CO2), whichgenerates electromagnetic energy having a wavelength in a range of 9.0to 10.6 microns. Water is chosen as the preferred fluid because of itsbiocompatibility, abundance, and low cost. The actual fluid used mayvary as long as it is properly matched (meaning it is highly absorbed)to the selected electromagnetic energy source (i.e. laser) wavelength.

The delivery system 55 for delivering the electromagnetic energyincludes a fiberoptic energy guide or equivalent which attaches to thelaser system and travels to the desired work site. Fiberoptics orwaveguides are typically long, thin and lightweight, and are easilymanipulated. Fiberoptics can be made of calcium fluoride (CaF), calciumoxide (CaO2), zirconium oxide (ZrO2), zirconium fluoride (ZrF),sapphire, hollow waveguide, liquid core, TeX glass, quartz silica,germanium sulfide, arsenic sulfide, germanium oxide (GeO2), and othermaterials. Other delivery systems include devices comprising mirrors,lenses and other optical components where the energy travels through acavity, is directed by various mirrors, and is focused onto the targetedcutting site with specific lenses. The preferred embodiment of lightdelivery for medical applications of the present invention is through afiberoptic conductor, because of its light weight, lower cost, andability to be packaged inside of a handpiece of familiar size and weightto the surgeon, dentist, or clinician. In industrial applications,non-fiberoptic systems may be used.

The nozzle 71 is employed to create an engineered combination of smallparticles of the chosen fluid. The nozzle 71 may comprise severaldifferent designs including liquid only, air blast, air assist, swirl,solid cone, etc. When fluid exits the nozzle 71 at a given pressure andrate, it is transformed into particles of user-controllable sizes,velocities, and spatial distributions.

FIG. 6 illustrates a control panel 77 for allowing user-programmabilityof the atomized fluid particles. By changing the pressure and flow ratesof the fluid, for example, the user can control the atomized fluidparticle characteristics. These characteristics determine absorptionefficiency of the laser energy, and the subsequent cutting effectivenessof the electromagnetically induced mechanical cutter. This control panelmay comprise, for example, a fluid particle size control 78, a fluidparticle velocity control 79, a cone angle control 80, an average powercontrol 81, a repetition rate 82, and a fiber selector 83.

The cone angle may be controlled, for example, by changing the physicalstructure of the nozzle 71. For example, various nozzles 71 may beinterchangeably placed on the electromagnetically induced mechanicalcutter. Alternatively, the physical structure of a single nozzle 71 maybe changed.

FIG. 7 illustrates a plot 85 of mean fluid particle size versuspressure. According to this figure, when the pressure through the nozzle71 is increased, the mean fluid particle size of the atomized fluidparticles decreases. The plot 87 of FIG. 8 shows that the mean fluidparticle velocity of these atomized fluid particles increases withincreasing pressure.

According to the present invention, materials are removed from a targetsurface by mechanical cutting forces, instead of by conventional thermalcutting forces. Laser energy is used only to induce mechanical forcesonto the targeted material. Thus, the atomized fluid particles act asthe medium for transforming the electromagnetic energy of the laser intothe mechanical energy required to achieve the mechanical cutting effectof the present invention. The laser energy itself is not directlyabsorbed by the targeted material. The mechanical interaction of thepresent invention is safer, faster, and eliminates the negative thermalside effects typically associated with conventional laser cuttingsystems.

The fiberoptic guide 23 (FIG. 5) can be placed into close proximity ofthe target surface. This fiberoptic guide 23, however, does not actuallycontact the target surface. Since the atomized fluid particles from thenozzle 71 are placed into the interaction zone 59, the purpose of thefiberoptic guide 23 is for placing laser energy into this interactionzone, as well. A novel feature of the present invention is the formationof the fiberoptic guide 23 of sapphire. Regardless of the composition ofthe fiberoptic guide 23, however, another novel feature of the presentinvention is the cleaning effect of the air and water, from the nozzle71, on the fiberoptic guide 23.

Applicants have found that this cleaning effect is optimal when thenozzle 71 is pointed somewhat directly at the target surface. Forexample, debris from the mechanical cutting are removed by the sprayfrom the nozzle 71.

Additionally, applicants have found that this orientation of the nozzle71, pointed toward the target surface, enhances the cutting efficiencyof the present invention. Each atomized fluid particle contains a smallamount of initial kinetic energy in the direction of the target surface.When electromagnetic energy from the fiberoptic guide 23 contacts anatomized fluid particle, the spherical exterior surface of the fluidparticle acts as a focusing lens to focus the energy into the waterparticle's interior.

As shown in FIG. 9, the water particle 101 has an illuminated side 103,a shaded side 105, and a particle velocity 107. The focusedelectromagnetic energy is absorbed by the water particle 101, causingthe interior of the water particle to heat and explode rapidly. Thisexothermic explosion cools the remaining portions of the exploded waterparticle 101. The surrounding atomized fluid particles further enhancecooling of the portions of the exploded water particle 101. Apressure-wave is generated from this explosion. This pressure-wave, andthe portions of the exploded water particle 101 of increased kineticenergy, are directed toward the target surface 107. The incidentportions from the original exploded water particle 101, which are nowtraveling at high velocities with high kinetic energies, and thepressure-wave, impart strong, concentrated, mechanical forces onto thetarget surface 107.

These mechanical forces cause the target surface 107 to break apart fromthe material surface through a “chipping away” action. The targetsurface 107 does not undergo vaporization, disintegration, or charring.The chipping away process can be repeated by the present invention untilthe desired amount of material has been removed from the target surface107. Unlike prior art systems, the present invention does not require athin layer of fluid. In fact, it is preferred that a thin layer of fluiddoes not cover the target surface, since this insulation layer wouldinterfere with the above described interaction process.

FIGS. 10, 11 and 12 illustrate various types of absorptions of theelectromagnetic energy by atomized fluid particles. The nozzle 71 ispreferably configured to produce atomized sprays with a range of fluidparticle sizes narrowly distributed about a mean value. The user inputdevice for controlling cutting efficiency may comprise a simple pressureand flow rate gauge 75 (FIG. 5) or may comprise a control panel as shownin FIG. 6, for example. Upon a user input for a high resolution cut,relatively small fluid particles are generated by the nozzle 71.Relatively large fluid particles are generated for a user inputspecifying a low resolution cut. A user input specifying a deeppenetration cut causes the nozzle 71 to generate a relatively lowdensity distribution of fluid particles, and a user input specifying ashallow penetration cut causes the nozzle 71 to generate a relativelyhigh density distribution of fluid particles. If the user input devicecomprises the simple pressure and flow rate gauge 75 of FIG. 5, then arelatively low density distribution of relatively small fluid particlescan be generated in response to a user input specifying a high cuttingefficiency. Similarly, a relatively high density distribution ofrelatively large fluid particles can be generated in response to a userinput specifying a low cutting efficiency. Other variations are alsopossible.

These various parameters can be adjusted according to the type of cutand the type of tissue. Hard tissues include tooth enamel, tooth dentin,tooth cementum, bone, and cartilage. Soft tissues, which theelectromagnetically induced mechanical cutter of the present inventionis also adapted to cut, include skin, mucosa, gingiva, muscle, heart,liver, kidney, brain, eye, and vessels. Other materials may includeglass and semiconductor chip surfaces, for example. A user may alsoadjust the combination of atomized fluid particles exiting the nozzle 71to efficiently implement cooling and cleaning of the fiberoptics 23(FIG. 5), as well. According to the presently preferred embodiment, thecombination of atomized fluid particles may comprise a distribution,velocity, and mean diameter to effectively cool the fiberoptic guide 23,while simultaneously keeping the fiberoptic guide 23 clean of particulardebris which may be introduced thereon by the surgical site.

Looking again at FIG. 9, electromagnetic energy contacts each atomizedfluid particle 101 on its illuminated side 103 and penetrates theatomized fluid particle to a certain depth. The focused electromagneticenergy is absorbed by the fluid, inducing explosive vaporization of theatomized fluid particle 101.

The diameters of the atomized fluid particles can be less than, almostequal to, or greater than the wavelength of the incident electromagneticenergy. In each of these three cases, a different interaction occursbetween the electromagnetic energy and the atomized fluid particle. FIG.10 illustrates a case where the atomized fluid particle diameter is lessthan the wavelength of the electromagnetic energy (d<λ). This casecauses the complete volume of fluid inside of the fluid particle 101 toabsorb the laser energy, inducing explosive vaporization. The fluidparticle 101 explodes, ejecting its contents radially. Applicants referto this phenomena as the “explosive grenade” effect. As a result of thisinteraction, radial pressure-waves from the explosion are created andprojected in the direction of propagation. The direction of propagationis toward the target surface 107, and in the presently preferredembodiment, both the laser energy and the atomized fluid particles aretraveling substantially in the direction of propagation.

The resulting portions from the explosion of the water particle 101, andthe pressure-wave, produce the “chipping away” effect of cutting andremoving of materials from the target surface 107. Thus, according tothe “explosive grenade” effect shown in FIG. 10, the small diameter ofthe fluid particle 101 allows the laser energy to penetrate and to beabsorbed violently within the entire volume of the liquid. Explosion ofthe fluid particle 101 can be analogized to an exploding grenade, whichradially ejects energy and shrapnel. The water content of the fluidparticle 101 is evaporated due to the strong absorption within a smallvolume of liquid, and the pressure-waves created during this processproduce the material cutting process.

FIG. 11 shows a case where the fluid particle 101 has a diameter, whichis approximately equal to the wavelength of the electromagnetic energy(d≈λ). According to this “explosive ejection” effect, the laser energytravels through the fluid particle 101 before becoming absorbed by thefluid therein. Once absorbed, the fluid particle's shaded side heats up,and explosive vaporization occurs. In this case, internal particle fluidis violently ejected through the fluid particle's shaded side, and movesrapidly with the explosive pressure-wave toward the target surface. Asshown in FIG. 11, the laser energy is able to penetrate the fluidparticle 101 and to be absorbed within a depth close to the size of theparticle's diameter. The center of explosive vaporization in the caseshown in FIG. 11 is closer to the shaded side 105 of the moving fluidparticle 101. According to this “explosive ejection” effect shown inFIG. 11, the vaporized fluid is violently ejected through the particle'sshaded side toward the target surface 107.

A third case shown in FIG. 12 is the “explosive propulsion” effect. Inthis case, the diameter of the fluid particle is larger than thewavelength of the electromagnetic energy (d>λ). In this case, the laserenergy penetrates the fluid particle 101 only a small distance throughthe illuminated surface 103 and causes this illuminated surface 103 tovaporize. The vaporization of the illuminated surface 103 tends topropel the remaining portion of the fluid particle 101 toward thetargeted material surface 107. Thus, a portion of the mass of theinitial fluid particle 101 is converted into kinetic energy, to therebypropel the remaining portion of the fluid particle 101 toward the targetsurface with a high kinetic energy. This high kinetic energy is additiveto the initial kinetic energy of the fluid particle 101. The effectsshown in FIG. 12 can be visualized as a micro-hydro rocket with a jettail, which helps propel the particle with high velocity toward thetarget surface 107. The exploding vapor on the illuminated side 103 thussupplements the particle's initial forward velocity.

The combination of FIGS. 10-12 is shown in FIG. 13. The nozzle 71produces the combination of atomized fluid particles which aretransported into the interaction zone 59. The laser 51 is focused onthis interaction zone 59. Relatively small fluid particles 131 explodevia the “grenade” effect, and relatively large fluid particles 133explode via the “explosive propulsion” effect. Medium sized fluidparticles, having diameters approximately equal to the wavelength of thelaser 51 and shown by the reference number 135, explode via the“explosive ejection” effect. The resulting pressure-waves 137 andexploded fluid particles 139 impinge upon the target surface 107.

FIG. 14 illustrates the clean, high resolution cut produced by theelectromagnetically induced mechanical cutter of the present invention.Unlike the cut of the prior art shown in FIG. 15, the cut of the presentinvention is clean and precise. Among other advantages, this cutprovides an ideal bonding surface, is accurate, and does not stressremaining materials surrounding the cut.

Although an exemplary embodiment of the invention has been shown anddescribed, many changes, modifications and substitutions may be made byone having ordinary skill in the art without necessarily departing fromthe spirit and scope of this invention.

What is claimed is:
 1. A method of mechanically removing portions of atarget surface, comprising the following steps: a user control acceptinga user input, which specifies a cutting efficiency wherein at least onephysical characteristic of atomized fluid particles from an atomizer iscontrolled by the user input; outputting atomized fluid particles fromthe atomizer into an interaction zone, the interaction zone beingdefined as a volume above the target surface; focusing or placing a peakconcentration of electromagnetic energy onto the atomized fluidparticles in the interaction zone, the electromagnetic energy having awavelength which is substantially absorbed by the atomized fluidparticles in the interaction zone; and the atomized fluid particles inthe interaction zone highly absorbing the electromagnetic energy,exploding, and imparting disruptive mechanical forces onto the targetsurface to hereby remove the portions of the target surface.
 2. Themethod of mechanically removing portions of a target surface accordingto claim 1, wherein the step of outputting atomized fluid particles fromthe atomizer into an interaction zone above the target surface includesa substep of outputting atomized water particles from the atomizer intothe interaction zone above the target surface.
 3. The method ofmechanically removing portions of a target surface according to claim 2,wherein the step of focusing or placing a peak concentration ofelectromagnetic energy onto the atomized fluid particles in theinteraction zone comprises a substep of focusing or placing a peakconcentration of electromagnetic energy from an erbium, chromium,yttrium scandium gallium garnet (Er, Cr:YSGG) solid state laser, whichgenerates electromagnetic energy having a wavelength of approximately2.78 microns, onto the atomized water particles in the interaction zone.4. The method of mechanically removing portions of a target surfaceaccording to claim 1, wherein the target surface comprises a tooth. 5.The method of mechanically removing portions of a target surfaceaccording to claim 1, wherein the step of outputting atomized fluidparticles from an atomizer includes a step of outputting atomized fluidparticles from an atomizer that is connected to an air supply line and awater supply line, wherein air and water are mixed by the atomizer toform the atomized fluid particles.
 6. The method of mechanicallyremoving portions of a target surface according to claim 5, herein theair supply line is operated under a relatively high pressure and thewater supply line is operated under a relatively low pressure.
 7. Themethod of mechanically removing portions of a target surface accordingto claim 6, wherein the atomized fluid particles have sizes narrowlydistributed about a mean value.
 8. A method of providingelectromagnetically induced mechanical cutting forces onto a targetsurface to thereby remove portions of the target surface, comprising thefollowing steps: inputting a user-specified combination of atomizedfluid particles, the user-specified combination of atomized fluidparticles corresponding to a user-specified average size, spatialdistribution, and velocity of atomized fluid particles; generating theuser-specified combination of atomized fluid particles, in response tothe user input device; placing the user-specified combination ofatomized fluid particles into an interaction zone, the interaction zonebeing defined as a volume above the target surface; and focusingelectromagnetic energy into the interaction zone, the electromagneticenergy having a wavelength which is substantially absorbed by a portionof atomized fluid particles of the user-specified combination ofatomized fluid particles in the interaction zone, the absorption of theelectromagnetic energy by the portion of atomized fluid particlescausing the portion of atomized fluid particles to explode and impartmechanical cutting forces onto the target surface.
 9. A method ofcontrolling a cutting efficiency of an electromagnetically inducedmechanical cutter, comprising the following steps: focusing or placing apeak concentration of electromagnetic energy into a volume adjacent to atarget surface; specifying at least one of a cutting resolution and apenetration level for the cutting efficiency; selecting one of aplurality of fluid spray nozzles, in response to a specification of thecutting resolution; selecting an upstream fluid pressure for theselected fluid spray nozzle, in response to a specification of thepenetration level; applying the upstream fluid pressure to the fluidspray nozzle, to thereby generate a user specified combination ofatomized fluid particles; and placing the user-specified combination ofatomized fluid particles into the volume adjacent to the target surface,the electromagnetic energy being substantially absorbed by theuser-specified combination of atomized fluid particles, theuser-specified combination of atomized fluid particles, upon absorbingthe electromagnetic energy, exploding and imparting mechanical cuttingforces onto the target surface.
 10. The method of controlling a cuttingefficiency of an electromagnetically induced mechanical cutter accordingto claim 8, the step of specifying at least one of a cutting resolutionand a penetration level for the cutting efficiency further comprisingthe following steps: specifying, via a user input, one of a highresolution cut and a low resolution cut; and specifying, via a userinput, one of a deep-penetration cut and a shallow-penetration cut. 11.The method of controlling a cutting efficiency of an electromagneticallyinduced mechanical cutter according to claim 10, wherein the step ofapplying the upstream fluid pressure to the fluid spray nozzle comprisesthe following substeps: generating a combination of atomized fluidparticles comprising relatively small fluid particles, in response to auser input specifying a high resolution cut; generating a combination ofatomized fluid particles comprising relatively large fluid particles, inresponse to a user input specifying a low resolution cut; generating acombination of atomized fluid particles which comprises a relativelylow-density distribution of fluid particles, in response to a user inputspecifying a deep-penetration cut; and generating a combination ofatomized fluid particles which comprises a relatively high-densitydistribution of fluid particles, in response to a user input specifyinga shallow-penetration cut.
 12. The apparatus for controlling a cuttingefficiency of an electromagnetically induced mechanical cutter accordingto claim 11, wherein the step of applying the upstream fluid pressure tothe fluid spray nozzle further comprises the following substeps:generating atomized fluid particles with relatively high kineticenergies, in response to at least one of a user specification for adeep-penetration cut and a user specification for a high resolution cut;and generating atomized fluid particles with relatively low kineticenergies, in response to at least one of a user specification for ashallow-penetration cut and a user specification for low resolution cut.